1. Field of the Invention
This invention relates to an apparatus for reading information marks and, more particularly, an apparatus for reading fluorescent information marks in the wood products industry.
2. Prior Art
This invention replaces a key entry operator who would key in the information from the marks to an automatic trimmer. Electronic devices already in the prior art include a black and white line camera which used fluorescent marks on a piece of lumber. A fluorescent light, but not a strobe, was used to excite the fluorescent marks. A central processing unit enhances the character recognition. Color could not be recognized.
In a lumber production operation, for example, producing two by fours, the cut lumber is graded twice. Once after it is first cut into 2.times.4 (greenend) and second, after kiln drying, at the planer end. Information marks are placed on the lumber which grade the quality of the lumber and require cutting some length off the two by four. An error rate is calculated from the misread or mis-entered information. If a mark is not entered or not read, it will be sorted into a rerun bin and run through the system again. A mis-trimmed board will count in the error rate.
The problems in this area include speed, accuracy and, in the electronic version, technical. The manual system requires a person to read the lumber marks and key the number into the trimmer. This invention is substantially quicker by means of the reading of the lumber marks electronically and eliminating the key-in requirement. Additionally, this invention is directly connected to the trimmer.
With respect to accuracy, eliminating the key-in increases accuracy by decreasing the opportunities for error. Furthermore, direct transfer from reader to trimmer enhance accuracy.
Technical problems, particularly reading a moving, bouncing, vibrating board, have limited electronic devices in the area. By use of a rapid strobe, the board appears stationary. Furthermore, the rapid strobe also eliminates any problem of uneven chain movement. Finally, the camera used is different from a linear (line) camera.